1. Field of the Invention
This invention relates generally to modulation of optical circuits and networks; and more particularly to method and apparatus providing faster switching or modulation speed with lower power than heretofore available.
2. Related Art
A seminal effort in this field is U.S. Pat. No. 4,988,157 of Jackel—assigned to Bell Communication. That patent teaches use of a chemically (to be more specific, electrolytically) creatable and destroyable bubble, and its implications on total internal reflection, for optical modulation.
U.S. Pat. Nos. 5,699,462 and 5,960,131 of Fouquet et al., and U.S. Pat. No. 5,978,527 of Donald, represent applications of the thermal-inkjet technology refinements of Hewlett Packard Company to light modulation or switching. Though faster than electrolysis, thermal effects operate on the order of milliseconds and accordingly are far from optimal in switching speed.
U.S. Pat. No. 5,619,600 of Pohl and U.S. Pat. No. 5,774,252 of Lin et al. represent entries in somewhat related fields on behalf of IBM and Texas Instruments, respectively; and Japanese publication 5-49055 of 1993 represents a related effort by Nippon Telegraph & Telephone Corporation. Pohl teaches tunneling of light through liquid metal, for pathlengths on the order of a fractional wavelength; possibly useful for kilohertz CW modulation, this technique too is relatively slow for switching.
As can now be seen, the related art remains subject to significant problems. The efforts outlined above—although praiseworthy—leave room for considerable refinement.